The present invention relates to a wireless terminal and a wireless base station, and more particularly, to a wireless terminal which allows time-divisional transmission to a first mobile wireless communication system and a second mobile wireless communication system, wherein the wireless base station can control a transmission timing of the wireless terminal.
In order to cope with a rapidly increasing demand for wireless communication, new wireless communication systems have been continuously created. Therefore, various methods are implemented as a method of switching a wireless communication system (hereinafter, referred to as ‘inter-system hand off’). The inter-system hand off includes hand off between mobile wireless communication systems and hand off between the mobile wireless communication system and a fixed wireless communication system. An example of the former is an inter-system hand off between cdma2000 1xEV-DO and cdma2000 1x and an example of the latter is an inter-system hand off between cdma2000 1xEV-DO and a wireless LAN.
The method of implementing the inter-system hand off is largely classified into two methods. One of them is a method in which a switching source wireless communication system and a switching destination wireless communication system are independent from each other, the wireless terminal autonomously switches a system of a communication target when determining that the inter-system hand off is necessary and then starts communication with the switching destination wireless communication system.
The other is a method in which the switching source wireless communication system and the switching destination wireless communication system are connected to each other through a network, and the wireless terminal previously starts the communication with the switching destination wireless communication system through the switching source wireless communication system to switch the system of the communication target. The latter has an advantage in that a switching time is shorter since the communication starts in advance. A method in which the communication of cdma2000 1x is performed on cdma2000 1xEV-DO through tunneling is disclosed in the 3gpp2, C. S0082 ver. 1.0, Circuit Services Notification Application Specification for cdma2000 High Rate Packet Data.
As data communication is paused during acquisition/exchange of parameters, authentication, etc. with the switching destination wireless communication system, a method in which a wireless terminal starts communication with a switching destination wireless communication system after autonomously switching a communication target system has a disadvantage that a service stop time is long from a user's viewpoint.
Meanwhile, since acquisition/exchange of parameters, authentication, etc. are performed in advance, a method of performing switching by previously performing communication with a switching destination wireless communication system through a switching source wireless communication system has an advantage that a service is not stopped. In this method, however, the switching source wireless communication system and the target wireless communication system need to be connected to each other through a network in advance and a structure of tunneling the communication with the switching destination wireless communication system needs to be established in the switching source wireless communication system. Therefore, this method has a disadvantage in that a usable case is limited.